System and method for applying a low frequency magnetic field to biological tissues

ABSTRACT

A system and method for applying a low strength, low frequency magnetic field therapy to biological tissues. A coil is excited with a low frequency oscillating current, e.g., 10-1000 Hz. The coil is, e.g., 5-200 turns, having a diameter of 2-20 mm, and produces a magnetic field strength of about 0.01-5 mTelsa at a distance of 1 cm from the coil, or a cover over the coil, into the tissue. The current is preferably controlled by a smartphone or other programmable device controlled by a downloadable app in accordance with a PEMF program which may be separately downloaded or updated, and may be provided through an audio jack. Alternately, a digital interface and/or wireless interface may control the current. An app on the smartphone may be used to control the frequency, amplitude/envelope modulation, waveform, duration, etc. of the oscillation. The coil may be in mineral housing with a simple filter, and TRRS-type audio jack.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. patent applicationSer. No. 17/074,557, filed Oct. 19, 2020, now U.S. Pat. No. 11,344,741,issued May 31, 2022, which is a Continuation of U.S. patent applicationSer. No. 15/809,684, filed Nov. 10, 2017, now U.S. Pat. No. 10,806,942,issued Oct. 20, 2020, which claims benefit of priority from, and is anon-provisional of, U.S. Provisional Patent Application No. 62/420,337,filed Nov. 10, 2016, the entirety of which are expressly incorporatedherein by reference.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

This invention pertains to a system and method for providing atherapeutic magnetic field at a frequency of about 5 Hz-50 kHz.

2. Discussion of Related Art

It is now well established that application of weak non-thermalelectromagnetic fields (“EMF”) can result in physiologically meaningfulin vivo and in vitro bioeffects. Time-varying electromagnetic fields,comprising rectangular waveforms such as pulsing electromagnetic fields(“PEMF”), and sinusoidal waveforms such as pulsed radio frequency fields(“PRF”) ranging from several Hertz, are clinically beneficial when usedas an adjunctive therapy for a variety of musculoskeletal injuries andconditions.

Wade, Brett, “A Review of Pulsed Electromagnetic Field (PEMF) Mechanismsat a Cellular Level: A Rationale for Clinical Use”, American Journal ofHealth Research. Vol. 1, No. 3, 2013, pp. 51-55. doi:10.11648/j.ajhr.20130103.13, also discusses various PEMF studies.Significant tissue healing effects, particularly with the modality PEMF,are likely the result of increased activity in non-excitable cells.Electromagnetic modalities include any modality which uses electricityand therefore generates both an electric field and a magnetic field. Inphysiotherapy practice, these electromagnetic modalities are generallyused to expedite recovery of soft tissue injuries or alleviate pain. Themovement of the electrons will cause ions to move towards the electrodesand thereby, ostensibly, affecting the physiology of the cell. Ions suchas calcium (Ca²⁺), potassium (K⁺), sodium (Na⁺), chlorine (Cl⁻), etc.Ions have numerous roles in the cellular physiology of cells. Themovement of ions through ion channels in the plasma membrane andorganelles have important roles in excitable and non-excitable cellssuch as nerve cell signal propagation, muscle contractions, energyproduction, etc. Electrotherapy education has traditionally attributedthe positive effects of electrotherapy to the effects of an electriccurrent causing a depolarization of excitable cells by the forcedmovement of ions (Na⁺ and K⁺) across the plasma membrane.

As previously described, negatively anions such as Cl⁻ will, in theory,be attracted to the positive charge of the externally applied electrodeand positively charged ions such as Na⁺ and K+ will be attracted to thenegative electrode. If the current used is a simple direct current(electrons flowing only in one direction), there would be build-up ofsame-charge ions concentrating in one area. This would have asignificant effect on local pH due to increased concentrations ofhydrochloric acid and sodium hydroxide leading to cause pain andcellular damage. Therefore, electrotherapy is usually the use of adirect current that is both pulsed and bi-directional to preventexcessive build-up of ions under an electrode. A paper published byPanagopoulos et al. (3) suggested a hypothesis whereby the externallyapplied electromagnetic field causes the ions to vibrate and when thisvibration reaches a critical point, this gives a false signal to thevoltage gated channels present in the membranes of eukaryotic cells.Once the channel receives a false signal, the gate may be forced toeither open or perhaps close but theoretically affecting the physiologyof the cell.

Panagopoulos et al. further describe how both the oscillating electricand magnetic fields can have similar effects on the free ions andconsequently the voltage gated channels. It has long been argued thatlow frequency; non-ionizing radiation has no significant bioactiveeffects on cells. This, in fact, has been the argument for why wirelesstechnology and the use of cellular telephones should have no negativeeffects to human health. The theory presented by Panagopoulos et al.suggests that, because of the inverse relationship between amplitude ofthe “ion's forced vibration” and frequency, lower frequencyelectromagnetic fields have the potential to be more bioactive. Theauthors provide a mathematical model which also explains how pulsedfields (on for a period and off for a period) are more bioactive thanstatic fields of the same parameters, and their calculations demonstratehow either pulsed electromagnetic fields or the time of onset or removalof an external field will be twice as active as non-pulsatile fields.The calculations support other observations which have found bioactiveeffects with pulsed fields of extremely low frequency.

While any of the electromagnetic modalities can theoretically attributetheir effects to both the electric and magnetic field, only PEMF isdesigned specifically to direct magnetic fields through the tissues tofacilitate healing. The purported mechanism of action of magnetic fieldson cells is has been suggested by Panagopoulos et al. Another paper byGanesan et al. (4) reviewed the literature for PEMF in the treatment ofarthritis. In addition to the effects suggested by Panagopoulos et al.,Ganesan et al., suggest that Ca²⁺ may be modulated by the externallyapplied magnetic field which in turn could affect many important voltagegated aspects of cell physiology including gene activation, signaltransduction, cAMP production, immune function, etc. Lookingspecifically at the effects of a pulsed magnetic field related toarthritis, Ganesan et al., review research which has found increasedchondrocyte production in joints exposed to PEMF. The authors alsoreview research which demonstrates a decrease in pro-inflammatorycytokines such as TNF-alpha and IL-6. In vitro studies have alsodemonstrated that PEMF has significant effects on both excitable andnon-excitable cells leading to osteogenesis (5) and chondrocyteproliferation (6). The research into positive effects with PEMF andmultiple sclerosis (MS) has found beneficial effects from PEMF usingmuch weaker intensities (7). Sandyk has shown positive results with MSin the picotesla intensities (8).

If the electric field is created by a movement of electrons, theresultant magnetic field is also capable of inducing electric currentsin a surrounding medium. The magnetic field created by the movingelectrons is essentially a field of virtual photons creating forcelines. This magnetic field is capable of causing movement of particleswith an electric charge such as ions. This force is known as a Lorentzforce. Since PEMF is not using an electric field per se, there is noelectron flow with frequency and pulse width suitable for stimulatingsensory or motor nerves. What the electric field and the magnetic fieldhave in common is the forced movement of ions. If an externally appliedelectromagnetic field can cause the forced movement of ions across aplasma membrane and we know that these movements can affect cellularphysiology, are there “windows” of frequency and intensity which may bemore effective? The parameters which have shown to be the most effectivewith PEMF in treating pathologies such as: bone healing, wound healing,ligament healing, and cartilage-healing range from 15-75 Hz and useintensities in the militesla range. Markov (9) has suggested “threeamplitude windows” with PEMF: 50-100 μT, 15-20 mT, and 45-50 mT.Summarized below are some of the effects on non-excitable cells exposedto PEMF.

Cells Mechanism, PEMF parameters, References

Chondrocytes Increased number of chondrocytes 75 Hz, 2.3 mT (Murray1985)

Osteoblasts Increased proliferation of osteoblasts 15 Hz, 0.1 mT (Marino1970)

Osteoclasts Decreased production of osteoclasts 7.5 Hz, 300 μs,

Neutrophils Saturates adenosine receptors leading to decreasedinflammatory cytokine cascade 75 Hz, 0.2 mT-3.5 mT (Doillon 1987)

Mononuclear Significant increased IL-1β & TNF-α (Pro inf. cytokines) 50Hz, 2.25 mT (Doillon 1986)

Fibroblasts Red. cAMP leads to increased proliferation of collagen cells15 Hz, 4.8 ms pulse (Basset 1981)

Endothelial Increased proliferation of endothelial cells leading toangiogenesis. 50 Hz, 1 mT (Brighton 1981)

In general, the PEMF mats use frequencies that range from 5-300 Hz whichis generally classified in a range of electromagnetic frequencies knownas extremely low frequency (ELF). The magnetic field intensities used bythese machines are usually in the micro and millitesla range.

The research to date has shown that the mechanisms by which PEMF worksare complicated and likely involve many pathways. It is clear thatcertain windows of frequency and intensity are capable of increasingmitosis in cells such as chondrocytes, osteoblasts, fibrocytes andendothelial cells. These effects will lead to improved healing time ofsoft tissues and bone. In addition to increasing cell metabolism,perhaps PEMF's greatest power is in its ability to ameliorate theeffects of inflammation by decreasing inflammatory cytokines. Thiseffect should give the practitioner cause to consider PEMF in thetreatment of numerous inflammatory conditions including, perhaps,autoimmune diseases such as MS. It is also conceivable, as suggested byGordon (2007), that another important effect of PEMF is the ability ofthe magnetic fields to restore “equilibrium in ROS (freeradical)/antioxidant chemistry. Gordon (2007) explains that since bothreactive oxygen species (ROS) free radicals such as superoxide anion(O.) and hydroxyl anion (OH.) are paramagnetic, they will be affected bya magnetic field. This forced vibration (similar to the effect on ionssuch as K⁺, Na⁺, Cl⁻, Ca²⁺) is thought to enhance the homeostasisbetween ROS and antioxidants. It is unequivocal that all chronicdiseases result from a lack of homeostasis between free radicals andantioxidants. While both free radicals and antioxidants are normal andvital for processes such as cellular respiration and immunity, animbalance could lead to cell and tissue death, DNA damage, and proteinand fat degradation.

U.S. 20110112352 discloses an apparatus and method for electromagnetictreatment, in which electromagnetic treatment devices are provided fortreatment of tissue. These are intended to apply energy within aspecific bandpass of frequencies of a target biological pathway, such asthe binding of Calcium to Calmodulin, and thereby regulate the pathway.The device provides for example, a field having an amplitude of betweenabout 1 μV/cm to about 100 mV/cm at the target tissue and a peak inducedmagnetic field between about 1 μT and about 20 μT. The control circuitgenerates a burst of waveforms having a burst duration of greater than0.5 msec and a burst period of between about 0.1 to about 10 seconds toproduce a signal that is above background electrical activity.

The use of most low frequency EMF has been in conjunction withapplications of bone repair and healing. As such, EMF waveforms andcurrent orthopedic clinical use of EMF waveforms comprise relatively lowfrequency components and are of low power, inducing maximum electricalfields in a millivolts per centimeter (mV/cm) range at frequencies underfive KHz. A linear physicochemical approach employing an electrochemicalmodel of cell membranes to predict a range of EMF waveform patterns forwhich bioeffects might be expected is based upon an assumption that cellmembranes, and specifically ion binding at structures in or on cellmembranes, are a likely EMF target.

Time-varying electromagnetic fields, comprising rectangular waveformssuch as pulsing electromagnetic fields, and sinusoidal waveforms such aspulsed radio frequency fields ranging from several Hertz to an about 15to an about 40 MHz range, may be clinically beneficial when used as anadjunctive therapy for a variety of musculoskeletal injuries andconditions.

U.S. Pat. No. 9,278,231 discloses a system for inducing cellularregeneration and/or degeneration processes and methods of treatmentbased on such processes through generating and applying a sequentiallyprogrammed magnetic field (SPMF) to the area to be treated. In the caseof regeneration and degeneration of cells, the pulsing frequencies arein the range of about 0.1 to about 2000 Hz based on the indication ofthe disease type. A magnetic field generating device is providedcomprising: a magnetically conductive hollow cylindrical base body; afunnel at one end of said magnetically conductive hollow cylindricalbase body which increases in diameter as it extends from the cylindricalbase body to a terminal rim-like portion; a magnetically conductiverod-like structure extending along a central axis through said hollowcylindrical base body into an interior of said funnel; and an electricalcoil wound circumferentially around the magnetic field generating devicefrom the other end of the hollow cylindrical base body to the rim-likeportion of the funnel.

U.S. Pat. No. 9,278,231 notes that electromagnetic fields of certainfrequency ranges and intensities are indigenous to living tissues and ithas been found that inciting the inherent resonance by exogenoustreatment using electromagnetic fields [EMF], electric fields, andmagnetic fields can induce cellular regeneration and degenerationprocesses. EMF in a range from 0.1-150 Hz have been reported tostimulate bone cells. It has also been reported that bone resorptionthat normally parallels disuse can be prevented or even reversed by theexogenous induction of electric fields. Electromagnetic fields below 10μV/cm, when induced at frequencies between 50 and 150 Hz for 1 h/day,are sufficient to maintain bone mass even in the absence of function.Reducing the frequency to 15 Hz makes the field extremely osteogenic.This frequency-specific sinusoidal field initiated more new boneformation than a more complex pulsed electromagnetic field (PEMF),though inducing only 0.1% of the electrical energy of the PEMF.

U.S. Pat. No. 8,968,172 discloses a cell excitation terminal and atherapeutic system using customized electromagnetic (EM) waves varyingdynamically with time for excitation include one or more EM wavegenerators, each of the EM wave generators is connected to a centralprocessing unit (CPU), and the CPU controls, according to a signaldetected by a human body status detection device, the EM wave generatorto send EM waves corresponding to a detected subject. The therapeuticsystem can perform remote management. A remote server optimizes andupdates therapeutic waveforms of a patient constantly according to atherapeutic effect of the patient, thereby improving the therapeuticeffect constantly.

U.S. Pat. No. 8,911,342 relates to an apparatus and a method forstimulating brain tissue with pulsed electromagnetic fields weaker thanthe limit for elicitation of the action potentials of the cells of thetissue to be stimulated, the apparatus comprising: at least oneelectrically conducting coil positioned at a bitemporal position suchthat hippocampus is stimulated by at least one magnetic field uponsupplying a pulse to said coil as well as a coil positioned at aoccipital and parietal position; and a pulse generation meansoperationally connected to said at least one coil for supplying a seriesof current pulses for conduction, allowing generation of pulsedelectromagnetic fields sufficiently strong to cause protein activation,and weaker than the limit for elicitation of the action potentials ofthe cells of the tissue to be stimulated.

U.S. Pat. No. 9,427,598 relates to methods of treating neurologicalinjury and conditions, in particular, traumatic brain injury andphysiological responses arising from injury or conditions. Thesetreatment methods can include the steps of generating a pulsedelectromagnetic field from a pulsed electromagnetic field source andapplying the pulsed electromagnetic field 1 in proximity to a targetregion affected by the neurological injury or condition to reduce aphysiological response to the neurological injury or condition.

U.S. Pat. No. 9,421,357 discloses systems, apparatuses, and methods forproviding non-transcranial electrical stimuli to a biological subjectmay employ a support structure, at least one waveform generator, and atleast a first electrode and a second electrode. The system can be sizedand dimensioned to be worn on a head of the biological subject andoperable to deliver non-transcranial electrical stimuli to at least oneof the temporomandibular joints of the biological subject.

The use of electrical energy to produce modifications in living tissueis well known. Electro-magnetic devices have been used to promotehealing of broken bones. Barker (1981). Additionally, use of pulsedelectro-magnetic fields (PEMF) to promote healing of bone tissue isdescribed in U.S. Pat. No. 4,315,503 to Ryaby, et al. and in U.S. Pat.No. 3,890,953 to Kraus, et al. Use of electro-magnetic energy to arrestarthritic pain has been disclosed in U.S. Pat. No. 3,902,502 to Liss, etal. There is little agreement so far amongst researchers in the field asto the most effective pulse wave form, frequency, and voltage level fortreatment of tissue disorders.

Wound repair involves cellular events such as cell migration,replication, synthesis and deposition of new connective tissue,remodeling and epidermal cell migration over dermal repair tissue. Manystudies suggest that these events may be influenced by endogenous andexogenous electric or magnetic fields in both soft and hard tissue.Electrical stimulation using direct electrical currents or inducedvoltages and currents has been shown to affect wound healing. Typicalmethods for the use of electric current in the promotion of healing arethose methods employing low intensity direct current (LIDC) and, morerecently, pulsed electromagnetic fields (PEMF). Electric current wasinitially employed to promote the healing bone fractures, especiallythose fractures demonstrating non-union. Several patents have issued formethods and devices for the use of PEMF's to promote bone healing. U.S.Pat. No. 3,915,151 issued to Kraus describes a magnetic coil device forthe induction of electric current by the application of a magnetic fieldto injured bones and related soft tissues. U.S. Pat. No. 4,233,965issued to Fairbanks describes a similar method and device using PEMF'sto induce an electric current for the healing of bone and connectivetissue, improved to achieve a deeper penetration of electrical current,especially for the treatment of arthritis. U.S. Pat. No. 4,556,051,issued to Maurer describes a device and method for promoting the healingof fractured bones and related connective tissue through thesimultaneous application of PEMF's and pulsed electric current in afixed phase relationship to produce a net current in the region of thefractured bone generally perpendicular to the plane of the fracture.U.S. Pat. No. 4,674,482 issued to Waltonen, et al describes a method anddevice for the promotion of vasoconstriction through the application ofPEMF's. The inventor describes the device as an “electric icepack.” Abiasing circuit is described that prevents the occurrence of a reversepolarity pulse upon the fall of the magnetic flux induced by the fall ofthe generated pulse, thereby diminishing high frequency ringing at thebeginning of a treatment signal and improving the promotion ofvasoconstriction. U.S. Pat. No. 4,461,300 issued to Christiensendescribes a method and device employing cathodic LIDC to promote thehealing of fractures and injuries to bones and related soft tissues. Aspecifically designed cathodic electrode implant assembly with aparticular method of implantation at the fracture or bone defect site isdisclosed.

U.S. Pat. No. 3,893,462 issued to Manning, which describes a method anddevice employing an undulating electrical signal having a wave formwhose rise time differs from its fall time, in turn producing a voltageat the tissue level that is bipolar with the amplitude and frequencycomponents of one polarity differing from those of the oppositepolarity, effecting the bioelectrical signals at the cellular or tissuelevel, thereby artificially stimulating the healing of the cells and/ortissue.

With respect to PEMF's, Bassett (1984), discloses that when a dynamic,magnetic field passes through a static conductor, such as wound tissue,an electric field is induced in the conductor, with voltages of 1.0 to1.5 millivolts per centimeter. Bassett states that the current inducedvaries with time. Bassett (1984) suggests that PEMF's promote collagengrowth. Goodman (1983), describes the stimulation of messenger RNAspecific activity by PEMF's of 0.1 G per micro second. Murray (1985)describes the increase in collagen production in cell cultures producedby low frequency PEMF's. The field was generated by a generator-drivenpair of Helmholtz-aiding air cored coils. Leaper (1985), on the otherhand, disclosed that a 400 Gauss magnetic field was found not to promotewound healing. McLeod (1987), describes the use of AC electric fields of0.1-1000 Hz frequency to promote proline incorporation into fibroblastpopulated collagen matrices.

Pawluk (2015) provides a review of PEMF for pain, and notes that staticEMFs have been used for centuries to control pain and other biologicproblems. After thousands of patient-years of use globally, very littlerisk has been found to be associated with MF therapies (Markov, 2004).Standards and guidelines for safety have been promulgated and published(ICNIRP, 2010). The primary precautions or contraindications relate toimplanted electrical devices, pregnancy (because of lack of data), andseizures with certain kinds of frequency patterns in seizure-proneindividuals. MFs affect pain perception in many different ways. Theseactions are both direct and indirect. Direct effects of MFs are onneuron firing, calcium ion movement, membrane potentials, endorphinlevels, nitric oxide, dopamine levels, acupuncture actions, and nerveregeneration. Indirect benefits of MFs from physiologic functionenhancement are on circulation, muscle, edema, tissue oxygen,inflammation, healing, prostaglandins, cellular metabolism, and cellenergy levels (Jerabek and Pawluk, 1996). Pain relief mechanisms vary bythe type of stimulus used (Takeshige and Sato, 1996). For example,needling to the pain-producing muscle, application of a static MF orexternal qigong, or needling to an acupuncture point all reduce pain bydifferent mechanisms. In guinea pigs, pain could be induced by reductionof circulation in the muscle (ischemia) and reduced by recovery ofcirculation. Muscle pain relief is induced by recovery of circulationdue to the enhanced release of acetylcholine as a result of activationof the cholinergic vasodilator nerve endings innervated to the muscleartery (Takeshige and Sato, 1996).

Several authors have reviewed the experience with PEMFs in EasternEurope (Jerabek and Pawluk, 1996) and elsewhere (Trock, 2000) andprovided a synthesis of the typical physiologic findings of practicaluse to clinicians, resulting from magnetic therapies. These include, ata minimum, reduction in edema and muscle spasm/contraction, improvedcirculation, enhanced tissue repair, and natural antinociception. Theseare the fundamentals of the repair of cell injury. PEMFs have been usedextensively in many conditions and medical disciplines, being mosteffective in treating rheumatic or musculoskeletal disorders. PEMFsproduced significant reduction of pain, improvement of spinal functions,and reduction of paravertebral spasms. In clinical practice, PEMFs havebeen found to be an aid in the therapy of orthopedic and trauma problems(Borg et al., 1996). The ability of PEMFs to affect pain is at least inpart dependent on the ability of PEMFs to positively affect humanphysiologic or anatomic systems. The human nervous system is stronglyaffected by therapeutic PEMFs (Prato et al., 2001). Animals exposed tostatic and extremely low-frequency (ELF) MFs are also affected by thepresence of light, which strengthens the effects of PEMFs (Prato et al.,1999). One of the most reproducible results of weak ELF MF exposure isan effect upon neurologic pain signal processing (Thomas and Prato,2002). This evidence suggests that PEMFs would also be an effectivecomplement for treating patients suffering from both chronic and acutepain.

The placebo response may explain as much as 40% of an analgesia responsefrom any pain treatment (Colloca et al., 2013), and needs to beaccounted for in research design to assure adequate sample sizes.However, aside from this aspect of accounting for the placebo effect,the central nervous system mechanisms responsible for the placeboresponse, that is, central cognitive and behavioral processes, can beaddressed directly in managing pain and include medications, hypnosis,mindfulness meditation, and psychotherapy. In addition, these placeboresponse-related central processes appear to be an appropriate targetwith magnetic therapies for managing pain. Amplifying MF manipulation ofcognitive and behavioral processes has been evaluated in animal behaviorstudies and in humans, affecting at the very least opiate receptors (DelSeppia et al., 2007). Therefore, amplifying the placebo response withcentrally focused MFs would generally be expected to be additive to painmanagement using MF therapies elsewhere on the body.

Cell injury itself involves multiple processes (Kumar, 2007), which, ifmitigated, can be expected to reduce the perception of pain and limitthe results of the cell injury. Therefore, this is the goal of clinicalmanagement. If the cause of pain cannot be reduced or eliminated, thenthe goals of pain management shift to reducing the perception of pain orblocking the pain signal traffic otherwise. Research on the use of PEMFsfor pain management focuses on the multiple mechanisms of the productionof pain. The primary mechanisms of the production of pain in localtissue in response to cell injury include, to varying degrees, edema,apoptosis or necrosis, diminished vascular supply, reduced cellularenergy production, and impaired repair processes. PEMF therapies addressmany of these different aspects of cell injury (Jerabek and Pawluk,1996). Magnetic therapy increases the threshold of pain sensitivity(Thomas and Prato, 2002) and activates the anticoagulation system(Khamaganova et al., 1993), which increases circulation to tissue. PEMFtreatment stimulates production of opioid peptides, activates mast cellsand increases electric capacity of muscular fibers, helps with edema andpain before or after a surgical operation (Pilla, 2013), increases aminoacid uptake (De Loecker et al., 1990), and induces changes intransmembrane energy transport enzymes, allowing energy coupling andincreased biologic chemical transport work.

Healthy humans normally have reduced pain perception and decreasedpain-related brain signals (Prato et al., 2001). Biochemical changes inthe blood of treated patients are found that support the pain reductionbenefit. PEMFs cause a significant improvement in normal standingbalance in adult humans (Thomas et al., 2001). PEMFs couple withmuscular processing or upper-body nervous tissue functions, whichindicate CNS sensitivity that likely improves central pain processing.

Various kinds of PEMFs have been found to reduce pain. For example,various MFs applied to the head or to an extremity, for 1-60 min, withintervals between exposures from several minutes to several hours,randomly sequenced with sham exposures allowed the study of brainreactions by various objective measures (Kholodov, 1998). EEGs showedincreased low-frequency rhythms. Low-frequency EEG rhythms may explainthe common perception of relaxation and sleepiness with ELF EMFs. Evenweak AC MFs affect pain perception and pain-related EEG changes inhumans (Sartucci et al., 1997). A 2 h exposure to 0.02-0.07 mT ELF MFscaused a significant positive change in pain-related EEG patterns.

The benefits of PEMF use may last considerably longer than the time ofuse. This is a common clinical observation. In rats, a single exposureproduces pain reduction both immediately after treatment and even at 24h after treatment (Cieslar et al., 1994). The analgesic effect is stillobserved at the 7th and 14th day of repeated treatment and even up to 14days after the last treatment. Repeated presentation of painful stimuliin rats can significantly elevate the threshold of response to painfulstimuli. One group (Fleming et al., 1994) investigated the ability ofmagnetic pulse stimuli to produce increases in pain thresholds,simulating thalamic pain syndrome. Exposure to the PEMFs increased thepain threshold progressively over 3 days. Pain suppression wasmaintained on the second and third days relative to other treatments.The pain threshold following the third MF exposure was significantlygreater than those associated with morphine and other treatments.Brain-injured and normal rats both showed a 63% increase in mean painthreshold. The mechanism may involve endorphins, having importantimplications for clinical practice and the potential for a reduction inreliance on habit-forming medications.

PEMFs promote healing of soft tissue injuries by reducing edema andincreasing resorption of hematomas (Markov and Pilla, 1995), therebyreducing pain. Low-frequency PEMFs reduce edema primarily duringtreatment sessions. PEMFs at very high frequencies applied for 20-30 mincause decreases in edema lasting several hours following an exposuresession. PEMF signals induce maximum electric fields in the mV/cm rangeat frequencies below 5 kHz.

Chronic pain often occurs from aberrant small neural networks withself-perpetuated neurogenic inflammation. It is thought thathigh-intensity pulsed magnetic stimulation (HIPMS) noninvasivelydepolarizes neurons and can facilitate recovery following injury (Ellis,1993). HIPMS, intensity up to 1.17 T, was used to study recovery afterinjury in patients with posttraumatic/postoperative low-back pain,reflex sympathetic dystrophy (RSD), neuropathy, thoracic outletsyndrome, and endometriosis. The outcome VAS difference was 0.4-5.2 withsham treatments versus 0-0.5 for active treatments. The author proposedthat the pain reduction was likely due to induced eddy currents.

Effects on the tissues of the body and the symptoms of pain have beenfound across a wide spectrum of electromagnetic frequencies, includinghigh-frequency PEMFs. For example, significant reductions in pain werefound in individuals with acute whiplash injuries using 27.12 MHz PEMFstimulation (Foley-Nolan et al., 1992). The same group (Foley-Nolan etal., 1990) had previously found that individuals with persistent neckpain lasting greater than 8 weeks had statistically significantlygreater improvement in their pain compared to controls. The controlswere then crossed over onto PEMF treatment and had similar results.

For more detailed discussion of the potential mechanisms of action ofMFs to treat pain, see Markov (2004). The author discusses some of theparameters that may be necessary to properly choose a therapeutic MFwith respect to the target tissue to be stimulated. The researchliterature on magnetic therapies for pain management is very variable indescribing the particular parameters of the magnetic therapy apparatusbeing studied. This leaves the clinician at a significant disadvantagein determining which MFs produce the best results for the givencondition being treated. Further, the author states, “during the past 25years more than 2 million patients have been treated worldwide for alarge variety of injuries, pathologies and diseases. This large numberof patients exhibited a success rate of approximately 80%, withvirtually no reported complications.” The author goes on to describe anumber of mechanisms of cellular action of EMFs that may be deemedresponsible for the therapeutic benefit in improving pain. In anotherstudy, Shupak et al. (2004) looked at possible mechanisms or influencingfactors for the effects of PEMFs on pain, especially on sensory and painperception thresholds. It appears that MF exposure does not affecttemperature perception but can increase pain thresholds, indicating ananalgesic effect. Based on the review by Del Seppia et al. (2007), itappears that at least one of the mechanisms involved in PEMF effects onpain and nociception is the opiate receptor. Another study in rats(Fleming et al., 1994) found that there was an analgesic effectcomparable to more noxious tactile stimulation, that is, stress-inducedanalgesia. There was an approximately 50% increase in the pain thresholdin response to electrical current stimulation.

In a study to gain a better understanding of pain perception (Robertsonet al., 2010), a functional magnetic resonance imaging study was done toassess how the neuromodulation effect of MFs influences the processingof acute thermal pain in normal volunteers. ELF MFs (from DC to 300 Hz)have been shown to affect pain sensitivity in snails, rodents, andhumans. Because of this research, it is unlikely that a pure placeboresponse is involved. This neuroimaging study found changes in specificareas of the brain with pain stimuli that are definitely modified bylow-intensity PEMF exposure.

Chronic pain is often accompanied with or results from decreasedcirculation or perfusion to the affected tissues, for example, cardiacangina or intermittent claudication. PEMFs have been shown to improvecirculation (Guseo, 1992). Pain syndromes due to muscle tension andneuralgias improve.

Peripheral neuropathy can be an extremely painful condition that is verychallenging to manage. Two randomized controlled studies failed to showsignificant results in diabetic peripheral neuropathy (DPN) (Wróbel etal., 2008; Weintraub et al., 2009). Another two studies showedsignificant improvements in DPN (Cieslar et al., 1995; Graak et al.,2009). There were significant methodological differences among thestudies.

A large study (Weintraub et al., 2009) was conducted to determinewhether repetitive and cumulative exposure to low-frequency PEMF to thefeet can reduce neuropathic pain (NP) and influence nerve regeneration.Two-hundred and twenty-five patients with DPN stage II or III wererandomized in a double-blind, placebo-controlled parallel study, across16 academic and clinical sites in 13 states to PEMF or sham (placebo)devices. They applied their treatments 2 h per day to their feet for 3months. Pain reduction scores were measured using a VAS, the neuropathypain scale (NPS), and the patient's global impression of change (PGIC).A subset of subjects underwent serial 3 mm punch skin biopsies fromthree standard lower-limb sites for epidermal nerve fiber density (ENFD)quantification. There was a significant dropout rate of 13.8%. The PEMFversus sham group had reductions in DPN symptoms on the PGIC (44% versus31%; p=0.04). There were no significant differences in the NP intensityon NPS or VAS. Of the 27 patients who completed serial biopsies, 29% ofthe PEMF group had an increase in the distal leg ENFD of at least 0.5SDs, while none did in the sham group (p=0.04). Those with increases indistal thigh ENFD had significant decreases in pain scores. Theconclusion was that PEMF at this dose was not effective specifically inreducing NP. However, neurobiological effects on ENFD, PGIC, and reduceditching scores were hopeful and suggest that future studies should beattempted with higher PEMF intensities 3000-5000 G, longer duration ofexposure, and a larger biopsy cohort. Since most of the therapeuticapproaches to DPN have poor success rates, relying mostly on thesuppression of pain with medications, this study is encouraging inactually demonstrating potential nerve regeneration improvements.

Another randomized, placebo-controlled, double-blind study (Wróbel etal., 2008) was conducted to assess an ELF PEMF effect on pain intensity,quality of life and sleep, and glycemic control in patients with painfuldiabetic polyneuropathy. Sixty-one patients were randomized into a studygroup of 32 patients exposed to a low-frequency, low-intensity MF or asham control group of 29 patients. Pain durations were greater than 2years in both groups. Treatments were for 3 weeks, 20 min a day, 5 daysa week. Questionnaires, completed at the beginning, after 1-3 and 5weeks, included SFMPQVAS (pain evaluation), EuroQol EQ-5D, and MOS SleepScale. Significant reductions in pain intensity were seen in both thestudy group, VAS 73 mm at baseline versus 33 mm after 3 weeks, andcontrols, VAS 69 mm at baseline versus 41 mm after 3 weeks. The extentof pain reduction did not differ significantly between the groups at anytime. The conclusion was that this low-intensity ELF PEMF, used for only3 weeks, had no advantage over sham exposure in reducing pain intensity.In the Weintraub study, patients were treated for 3 months, providing alonger opportunity to produce sustainable changes in the tissues. Sinceneuropathy is a very stubborn problem to treat, it is likely that bothof these neuropathy studies were too short for the severity ofneuropathy present, treatment protocols, measures, and equipment used.

In another study (Graak et al., 2009) on NP, using low-power,low-frequency PEMF of 600 and 800 Hz, 30 patients, 40-68 years of agewith DPN stages N1a, N1b, N2a, were randomly allocated to three groupsof 10 in each. Groups 1 and 2 were treated with low-power 600 and 800 HzPEMF, respectively, for 30 min for 12 consecutive days. Group 3 servedas control on usual medical treatment. Pain and motor nerve conductionparameters (distal latency, amplitude, nerve conduction velocity) wereassessed before and after treatment. They found significant reduction inpain and statistically significant (p<0.05) improvement in distallatency and nerve conduction velocity in experimental Groups 1 and 2.Using this particular protocol, low-frequency PEMF was seen to reduce NPas well as for retarding the progression of neuropathy even when appliedfor only a short span of time. What could happen with longer-termtreatment remains to be determined.

Thirty-one patients with diabetes mellitus (type I and II), with intensesymptoms of neuropathy, were treated (Cieslar et al., 1995). They had 20exposures to variable sinusoidal PEMF, 40 Hz, 15 mT, every day for 12min. Reduction of pain and paresthesias, vibration sensation, andimproved muscle strength was seen in 85% of patients, all significantlybetter than sham controls.

Carpal tunnel syndrome is another form of neuropathy, affecting themedian nerve at the wrist. There are many different approaches to thetreatment of carpal tunnel syndrome, including surgery, with varyingsuccess. In a randomized, double-blinded, placebo-controlled trial(Weintraub and Cole, 2008), a commonly commercially availablecombination of simultaneous static and dynamic, rotating time-varyingdynamic MFS was used to treat the wrist. There was a significantreduction of deep pain. Ten months of active PEMF resulted inimprovement in nerve conduction and subjective improvement onexamination (40%), pain scores (50%), and a global symptom scale (70%).

The neuropathy of postherpetic neuralgia, a very common and painfulcondition, often medically resistant, responded to PEMF (Kusaka et al.,1995). A combination static and pulsed MF device was placed on thepain/paresthesia areas or over the spinal column or limbs. Treatmentscontinued until symptoms improved or adverse side effects occurred.Therapy was effective in 80%. This treatment approach shows thattreatment for pain problems may either be localized to the area of painor over the spinal column or limbs, away from the pain. Treatment overthe appropriate related spinal segment offers the opportunity tointerrupt the afferent pain signal traffic to the brain. This approachhas been frequently used with success in Eastern European studies(Jerabek and Pawluk, 1996). Another author reported a more generalclinical series in postherpetic pain in which better results happened inpatients simultaneously suffering from neck and low-back pain (Di Massaet al., 1989).

Posttraumatic, late-stage RSD, or now called regional complex painsyndrome (CRPS), a form of neuropathy, is very painful and largelyuntreatable by standard medical approaches. In one report, ten 30 minPEMF sessions of 50 Hz followed by a further 10 sessions at 100 Hz plusphysiotherapy and medication reduced edema and pain at 10 days(Saveriano and Ricci, 1989). There was no further improvement at 20days. The author had a personal case treated with a 27.12 MHz PEMFsignal, in a nurse who was almost completely disabled in her left upperextremity. She used her device for about an hour a day. Within about 1month, she had about 70% recovery, and within 2 months, she hadessentially normal function with no further sensitivity to touch,changes in temperature, etc. She maintained her recovery with continuedtreatments in the home setting.

Musculoskeletal conditions, especially with related pain, are mostfrequently treated with MF therapies. Among these, one of the mostcommon conditions is lumbar arthritis, as a cause of back pain. Chroniclow-back pain affects approximately 15% of the US population duringtheir lifetime (Preszler, 2000). Given the current treatment optionsavailable through conventional medical therapy, with their attendantrisks, there is a large unmet need for safe and effective alternativetherapies (Institute of Medicine, 2005).

PEMFs of 35-40 mT give relief or elimination of pain about 90%-95% ofthe time for lumbar OA, improve results from other rehabilitationtherapies, and secondarily, additionally improve related neurologicsymptoms (Mitbreit et al., 1986). Even PEMFs of 0.5-1.5 mT used at thesite of pain and related trigger points also help (Rauscher and VanBise, 2001). Some patients remained pain free 6 months after treatment.

In a series of 240 patients treated in an orthopedic practice withPEMFs, patients had decreased pain (Schroter, 1976) from rheumaticillnesses, delayed healing process in bones, and pseudoarthritis,including those with infections, fractures, aseptic necrosis, venous andarterial circulation, RSD (all stages), osteochondritis dissecans,osteomyelitis, and sprains and strains and bruises. The clinicallydetermined success rate approached 80%. About 60% of loosened hipprostheses have subjective relief of pain and walk better, without acane. Even so, x-ray evidence of improvement was seen periodically, asevidenced by cartilage/bone reformation, including the joint margin. Ifthe goal in pain management is to heal the underlying tissue, not justmanage symptoms, evidence, typically from imaging studies, can drive theduration of treatment to obtain the most long-lasting and more permanentresults.

The use of PEMFs is rapidly increasing and extending to soft tissue fromits first applications to hard tissue (Pilla, 2013). EMF in currentorthopedic clinical practice is frequently used to treat delayed andnonunion fractures, rotator cuff tendinitis, spinal fusions, andavascular necrosis, all of which can be very painful. Clinicallyrelevant response to the PEMF is generally not always immediate,requiring daily treatment for upward of a year in the case of nonunionfractures. PRF applications appear to be best for the reduction of painand edema. The acute tissue inflammation that accompanies the majorityof traumatic and chronic injuries is essential to the healing process;however, the body often over-responds in the chronic lesion situation,and the resulting edema causes delayed healing and chronic pain. Edemareduction is an important target for PRF and PEMF applications.

Even chronic musculoskeletal pain treated with MFs for only 3 days, onceper day, can eliminate and/or maintain chronic musculoskeletal pain(Stewart and Stewart, 1989). Small, battery-operated PEMF devices withvery weak field strengths have been found to benefit musculoskeletaldisorders (Fischer, 2002). Because of the low strength used, treatmentat the site of pain may need to last between 11 and 132 days, betweentwo times per week, 4 h each, and, if needed, continuous use. Use atnight could be near the head, for example, beneath the pillow, tofacilitate sleep. Pain scale scores are significantly better in themajority of cases. Conditions that can be considered for treatment arearthritis, lupus erythematosus, chronic neck pain, epicondylitis,patellofemoral degeneration, fracture of the lower leg, and RSD/CRPS.

Back pain or whiplash syndrome treated with a very low-intensity (up to30 μT) PEMF twice a day for 2 weeks along with usual pain medicationsrelieves pain in 8 days in the PEMF group versus 12 days in the controls(Thuile and Walzl, 2002). Headache is halved in the PEMF group, and neckand shoulder/arm pain improved by one-third versus medications alone.PEMFs have been found (Kjellman et al., 1999) to have more benefit inthe treatment of neck pain in some research, compared to physicaltherapy, for both pain and mobility.

A blinded randomized study was conducted to compare European spa therapy(ST) with PEMF therapy in chronic neck pain (Forestier et al., 2007a).There was significantly greater improvement in the PEMF group than theST group (p=0.02). As part of the earlier study, the authors also did acost-benefit analysis (Forestier et al., 2007b).

One group evaluated pain and swelling after distal radius fracturesafter an immobilization period of 6 weeks (Cheing et al., 2005).Eighty-three patients were randomly allocated to receive 30 min ofeither ice plus PEMF (group A), ice plus sham PEMF (group B), PEMF alone(group C), or sham PEMF for 5 consecutive days (group D). All had astandard home exercise program. Outcome measures included a VAS forrecording pain, volume displacement for measuring the swelling of theforearm, and a handheld goniometer for measuring the range of wristmotions. They were assessed, before treatment, and on days 1, 3, and 5during treatment. At day 5, a significantly greater cumulative reductionin VAS as well as improved ulnar deviation ROM was found in group A thanthe other three groups. For volumetric measurement and pronation,participants in group A performed better than subjects in group D butnot those in group B. The end result was that the addition of PEMF toice therapy produces better overall treatment outcomes than ice alone,or PEMF alone, in pain reduction and ulnar ROM. This study points outthe cumulative benefit of using both PEMFs and standard therapy, atleast in radial fractures.

Many therapeutic approaches for treatment of lateral epicondylitis(tennis elbow) have been used, including local steroid injection andsurgery. PEMFs have been found as a useful and safe candidate therapy.One group tested the efficacy of PEMF compared to sham PEMF and localsteroid injection (Uzunca et al., 2007). Sixty patients with lateralepicondylitis were randomly and equally distributed into three groups asfollows: group I received PEMF, group II sham PEMF, and group III acorticosteroid+anesthetic agent injection. Pain levels during rest,activity, nighttime, resisted wrist dorsiflexion, and forearm supinationwere investigated with VAS and algometer. All patients were evaluatedbefore treatment, at the third week, and the third month. VAS valuesduring activity and pain levels during resisted wrist dorsiflexion weresignificantly lower in group III than group I at the third week. Group Ipatients had lower pain during rest, activity, and nighttime than groupIII at the third month. PEMF appears to reduce lateral epicondylitispain better than sham PEMF. Corticosteroid and anesthetic agentinjections can be used in patients for rapid return to activities, alongwith PEMFs to produce a longer-standing benefit.

Another randomized sham-controlled study (Devereaux et al., 1985) onlateral humeral epicondylitis (tennis elbow) involved 30 patients withboth clinical and thermographic evidence of tennis elbow. PEMFtreatment, consisted of 15 Hz, delivering 13.5 mV and using a figure ofeight coil with the loops over each epicondyle for 8 h a day in one ortwo sessions, for a minimum period of 8 weeks. They were significantimprovements in grip strength at 6 weeks, with a slight decrease indifference at 8 weeks. There was little difference in the first 4 weeks.Since there were only 15 subjects in each treatment group, this studywas probably underpowered for most of the other measurement indicesused.

Osteoarthritis (OA) affects about 40 million people in the UnitedStates. OA of the knee is a leading cause of disability in the elderly.Medical management is often ineffective and creates additionalside-effect risks. Many patients with OA of the knee/s undergo many softtissue and intra-articular injections, physical therapy, and many,eventually, arthroscopies or joint replacements. An ELF sawtooth wave,50 μT, whole-body and pillow applicator system has been in use for about20 years in Europe. In one study using the system, applied 8 min twice aday for 6 weeks, it was shown to improve knee function and walkingability significantly (Pawluk et al., 2002). Pain, general condition,and well-being also improved. Medication use decreased. Plasmafibrinogen, C-reactive protein (a sign of inflammation), and thesedimentation rate all decreased by 14%, 35%, and 19% respectively.Sleep disturbances often contribute to increased pain perception. It wasfound to improve sleep, with 68% reporting good/very good results. Evenafter 1 year follow-up, 85% claim a continuing benefit in painreduction. Medication consumption decreases from 39% at 8 weeks to 88%after 8 weeks.

In a randomized, placebo-controlled study (Ay and Evcik, 2009), PEMF of50 Hz, 105 μT, applied for 30 min, was used in 55 patients with grade 3OA for only 3 weeks for pain relief and enhancing functional capacity ofpatients with knee OA. Pain improved significantly in both groupsrelatively equally (p<0.000). However, there was significant improvementin morning stiffness and activities of daily living (ADL) compared tothe control group. They did not find a beneficial symptomatic effect ofPEMF in the treatment of knee OA in all patients.

In a rheumatology clinic study of knee OA (Pipitone and Scott, 2001), 75patients received active PEMF treatment by a unipolar magnetic device orplacebo for 6 weeks. The 9 V battery-operated device was <0.05 mT with alow-frequency coil of 2 kHz plus harmonics up to 50 kHz modulated on a3, 7.8, or 20 Hz base frequency and an ultrahigh frequency coil with a250 MHz modulated frequency plus harmonics of the same modulation as theLF coil. Patients were instructed to use the magnetic devices threetimes a day. The 7.8 Hz modulation frequency was prescribed for themorning and afternoon treatments, while the 3 Hz modulation frequencywas prescribed for the evening. Baseline assessments showed that thetreatment groups were equally matched. Analysis at follow-up showedgreater between group improvements in global scores of health status.Paired analysis showed significant improvements in the actively treatedgroup in objective function, pain, disability, and quality of life atstudy end compared to baseline. These differences were not seen in theplacebo-treated group.

In another randomized, double-blind, placebo-controlled clinical trialof knee OA in Denmark (Thamsborg et al., 2005), 83 patients had two 2 hof daily treatment, 5 days per week for 6 weeks. They were reevaluatedat 2 and 6 weeks after treatment. Again, objective standardized measureswere used. There was a significant improvement in ADL, stiffness, andpain in the PEMF-treated group. In the control group, there was noeffect on ADL after 2 weeks and a weak change in ADL after 6 and 12weeks. Even the control group had significant reductions in pain at allevaluations and in stiffness after 6 and 12 weeks. There were nobetween-group differences in pain over time. ADL score improvements forthe PEMF-treated group appeared to be less with increasing age. Whengroups were compared, those <65 years of age had significant reductionin stiffness. While this tended to be a negative study, when looking atbetween-group comparisons, there were indications of improvement in ADLsand stiffness, especially in individuals younger than 65.

Twenty-seven OA patients treated with PEMF in a tube-like coil devicefor 18 half-hour exposures over 1 month had an average improvement of23%-61% compared to 2%-18% in the placebo group (Trock et al., 1993).They were evaluated at baseline, midpoint of therapy, end of treatment,and 1 month later. The active treatment group had decreased pain andimproved functional performance. Another study reported by the samegroup (Trock et al., 1994), including 86 patients with OA of the kneeand cervical spine, showed significant changes from baseline for thetreated patients at the end of treatment and at 1-month follow-up.Placebo patients also showed improvement but with less statisticalsignificance at the end of treatment and had lost significance for mostvariables at 1-month follow-up. The study patients showed improvementsin pain, pain on motion, patient overall assessment, and physicianglobal assessment.

One study (Sutbeyaz et al., 2006) looked at the effect of PEMFs on pain,ROM, and functional status in patients with cervical osteoarthritis(COA). Thirty-four patients were included in a randomized double-blindstudy. PEMF was administrated to the whole body using a 1.8×0.6 m sizewhole body mat. They were on the mat for 30 min per session, twice a dayfor 3 weeks. Pain levels in the PEMF treatment group decreasedsignificantly after therapy (p<0.001), with no change in the sham group.Active ROM, neck muscle spasm, and disability (NPDS) scores alsoimproved significantly after PEMF therapy (p<0.001). No change was seenin the sham group. This study shows that PEMFs can give significant painreduction in neck arthritis and can be used alone or with othertherapies to give even greater benefits.

A 50 Hz pulsed sinusoidal MF, 35 mT field PEMF for 15 min, 15 treatmentsessions, improves hip arthritis pain in 86% of patients. Averagemobility without pain improved markedly (Rehacek et al., 1982).Forty-seven patients with periarthritis of the shoulder who werereceiving outpatient physical therapy were randomized using a controlledtriple-blind study design to conventional physical therapy orconventional physical therapy with pulsed MF therapy (Leclaire andBourgouin, 1991). They received treatments three times a week for amaximum of 3 months. PEMF therapy was applied 30 min at a time at threedifferent frequencies 10/15/30 Hz with matched intensities of 3/4/6 mTover the course of the therapy program. This study showed nostatistically significant benefit from magnetotherapy in the pain score,ROM, or improvement of functional status in patients with periarthritisof the shoulder. There appeared to be a trend toward slightly worsebaseline function of the magnetic therapy group. This would thereforesuggest that treatment was not carried out for a sufficient time. Animprovement in the design of the study would have been to follow theindividuals until they had achieved either goal recovery or fullrecovery, as would happen in clinical practice. Another possibility forthe lack of benefit for the pulsed magnetic therapy group is that thefrequencies and intensities used are not optimized for this particularcondition, given the length and the frequency of treatments per week.

Fibromyalgia (FM) is a complex syndrome, primarily affecting women.PEMFs can frequently be very helpful. In one study (Sutbeyaz et al.,2009), 56 women with FM, aged 18-60 years, were randomly assigned toeither PEMF or sham therapy, 30 min per session, twice a day for 3weeks. Treatment outcomes were assessed after treatment and at 4 weeks,showing significant improvements in test scores at the end of therapyand at 4-week follow-up. The sham group also showed improvement at thistime on all outcome measures except the specific FM questionnaire. So,low-frequency PEMF therapy can improve at least some general FMsymptoms. A low-intensity PEMF (400 μT) in a portable device fitted totheir head was found to help FM. In a randomized, double-blind,sham-controlled clinical trial (Thomas et al., 2007), patients witheither chronic generalized pain from FM (n=17) or chronic localizedmusculoskeletal or inflammatory pain (n=15) were exposed in treatmentstwice daily for 40 min over 7 days. A VAS scale was used. There was apositive difference with PEMF over sham treatment with FM, although notquite reaching statistical significance (p=0.06). The same level ofbenefit was not seen in those without FM. In patients with other causesof chronic, nonmalignant pain, either longer periods of exposure arenecessary or other approaches need to be considered.

The effect of specific PEMF exposure on pain and anxiety ratings wasinvestigated in two patient populations (Shupak et al., 2006). Adouble-blind, randomized, placebo-controlled parallel design was used onthe effects of an acute 30 min MF exposure (less than or equal to 400μT; less than 3 kHz) on VAS-assessed pain and anxiety ratings in femaleRA and FM patients who received either the PEMF or sham exposuretreatment. A significant pre-post effect was present for the FMpatients, p<0.01. There was no significant reduction in VAS anxietyratings pre-to-post-exposure.

An in vivo study of PEMFs (Shafford H L, et al. 2002) was done in dogspostoperatively after ablation of ovaries and uterus to see how pain isaffected and interacts with postoperative morphine analgesia. Sixteenhealthy dogs were examined within 6 h postoperation at eight differenttime points. There were four groups: (1) control group (NaCladministration), (2) postoperative PEMF exposure (NaCl administration),(3) postoperative morphine application, and (4) postoperative morphineapplication plus PEMF exposure. The PEMF was 0.5 Hz, exposureintermittent, 20 min field on/20 min field off for 6 h, whole-bodyexposure. At 30 min, the total pain score for group 4 was significantlyless than for the control group, but not significantly different fromgroup 2 or 3. The results suggest that PEMF may augment morphineanalgesia or be used separately postoperatively after invasive abdominalprocedures.

After breast augmentation surgery, patients (Hedén and Pilla, 2008)applied a portable and disposable noninvasive, high-frequency andlow-intensity PEMF device in a double-blind, randomized,placebo-controlled study. Healthy females undergoing breast augmentationfor aesthetic reasons were separated into three cohorts: (n=14)receiving bilateral PEMF treatment, (n=14) receiving bilateral shamdevices, and (n=14) an active device to one breast and a sham device tothe other breast. Pain levels were measured twice daily through theseventh day after surgery (POD 7), and postoperative analgesic use wasalso tracked. VAS scores decreased in the active cohort by almost threetimes the sham cohort by POD 3 (p<0.001) and persisted at this level toPOD 7. Postoperative pain medication use decreased nearly three timesfaster in the active versus the sham cohorts by POD 3 (p<0.001). Theseresults can be extended to include the use of this form of PEMF for thecontrol of almost any situation of postoperative pain, especiallyinvolving surgery on superficial physical structures.

In another surgical study, this time post breast reduction forsymptomatic macromastia, PEMFs were studied, not only on their resultson postoperative pain, but also on potential mechanisms, includingchanges to cytokines and angiogenic factors in the wound bed (Rodhe etal., 2010). Twenty-four patients were randomized in a double-blind,placebo-controlled, randomized fashion to a sham control or alow-intensity 27.12 Hz PEMF configured to modulate thecalmodulin-dependent nitric oxide signaling pathway. Pain levels weremeasured by VAS, and narcotic use was recorded. The PEMF used produced a57% decrease in mean pain scores at 1 h (p<0.01) and a 300% decrease at5 h (p<0.001), persisting to 48 h postoperatively in the active versusthe control group, along with a concomitant 2.2-fold reduction innarcotic use in active patients (p=0.002). Mean IL-1β in wound exudateswas 275% lower (p<0.001), suggesting fairly rapid reductions in acuteposttraumatic inflammation.

On the other hand, some research has found a lack of benefit of PEMFspostoperatively. Pain after elective inguinal hernia repair wasevaluated in a double-blind randomized, non-PEMF controlled trial usinga high-frequency low-intensity portable PEMF device (Reed et al., 1987).The device had an output rate of 320 Hz, pulse width of 60 μs, andmaximum power output of 1 W. Treatment was 15 min twice a day, over andunder the thigh. VAS at 24 and 48 h postoperatively showed no differencebetween treated and untreated groups. This study most likely usedtreatment times that were too short for the intensities used, and theelectrodes were placed remote to the actual wound, not over the surgicalsite.

Severe joint inflammation following trauma, arthroscopic surgery, orinfection can damage articular cartilage; thus, every effort should bemade to protect cartilage from the catabolic effects of proinflammatorycytokines and stimulate cartilage anabolic activities. A pilot,randomized, prospective, and double-blind study (Zorzi et al., 2007) wasdone to evaluate the effects of PEMFs (75 Hz, rectangular) afterarthroscopic treatment of knee cartilage. Patients with knee pain wererecruited and treated by arthroscopy with chondroabrasion and/orperforations and/or radio frequencies. There were two groups:lower-intensity control (MF at 0.05 mT) and active (MF of 1.5 mT). PEMFswere used for 90 days, 6 h per day. Objective measures were used beforearthroscopy, and after 45 and 90 days, the use of anti-inflammatories(NSAIDs) was recorded. Three-year follow-up interviews were also used(n=31). Knee score values at 45 and 90 days were higher in the activegroup at 90 days (p<0.05). NSAID use was 26% in the active group and 75%in the control group (p=0.015). At 3-year follow-up, the percentcompletely recovered was higher in the active group (p<0.05).

Anterior cruciate ligament reconstruction, now a common surgicalprocedure, is usually performed by a minimally invasive arthroscopicapproach. Even so, arthroscopy may elicit an inflammatory joint reactiondetrimental to articular cartilage. PEMFs would be expected to mitigatesome of these inflammation reactions. To study this possibility, aprospective, randomized, and double-blind study was done on 69 patientswith a 75 Hz, 1.5 mT device, 4 h per day for 60 days versus sham device(Benazzo et al., 2008). At follow-up, active treatment patients showed astatistically significant faster recovery (p<0.05). The use ofanti-inflammatories was less frequent (p<0.05). Joint swelling andreturn to normal ROM occurred faster (p<0.05). The 2-year follow-up didnot show statistically significant difference between the two groups. Inaddition, a subset analysis of 29 patients (15 in the active group; 14in the placebo group) who concurrently had meniscectomy, function scoresbetween the two groups were even larger than observed in the wholestudy. So, this particular PEMF signal is expected to shortenpostoperative recovery time and limit joint inflammation.

Noninflammatory chronic pelvic pain syndrome (CPPS) can be quitedisabling in both men and women, frequently with no adequate treatmentoptions. A study (Leippold et al., 2005) was designed to prospectivelyevaluate sacral magnetic stimulation as a treatment option for patientswith noninflammatory CPPS (CPPS, category IIIB). Fourteen men weretreated with sacral magnetic stimulation, 10 treatment sessions once aweek for 30 min at a frequency of 50 Hz. Twelve of fourteen men reportedimprovement but only during the time of stimulation. Inventory scoresbefore and after treatment did not change. There was no sustained effectbeyond the time of stimulation on the mean scores for pain, micturitioncomplaints, or quality of life. Sacral magnetic stimulation in patientswith CPPS IIIB reduces pain only during stimulation. The fact the painrelief is obtained during treatment is notable and valuable. Becausethis level of frequency of treatments is less likely to induce healingin the tissues causing the pain syndrome, it may be reasonable to expectonly a reduction in pain during the treatment course and not a moreenduring benefit. While this treatment approach does not appear to beuseful, it remains to be seen whether a change in the protocol mayproduce more enduring results.

Gynecologic pelvic pain may also benefit from PEMFs. A high-voltage,high intensity, pulsed stimulation (1-30 pulses/second) system(Jorgensen et al., 1994) was used in the setting of ruptured ovariancysts, postoperative pelvic hematomas, chronic urinary tract infection,uterine fibrosis, dyspareunia, endometriosis, and dysmenorrhea. Ninetypercent of patients experienced marked rapid relief from pain, with painsubsiding within 1-3 days after PEMF treatment, eliminatingsupplementary analgesics.

In dentistry, periodontal disease may cause bone resorption severeenough to require bone grafting. Grafting is followed by moderate painpeaking several hours afterward. Repeated PEMF exposure for 2 weekseliminates pain within a week. Even single PEMF exposure to the face for30 min of a 5 mT field and related conservative treatment produce muchlower pain scores versus controls (Tesic et al., 1999).

Results of PRF PEMF in a case series either eliminates or improves, evenat 2 weeks following therapy, pain in 80% of patients with pelvicinflammatory disease, 89% with back pain, 40% with endometriosis, 80%with postoperative pain, and 83% with lower abdominal pain of unknowncause (Punnonen et al., 1980).

PEMFs have been found to be helpful in headaches. For migraineheadaches, high-frequency (5361 gHz) PEMFs applied to specificacupuncture points on the inner thighs for at least 2 weeks areeffective short-term therapy (Sherman et al., 1999). Longer exposureslead to greater reduction of headache activity. One month after atreatment course, 73% of patients report decreased headache activityversus 50% of placebo treatment. Another 2 weeks of treatment after the1-month follow-up gives an additional 88% decrease in headache activity.Patients with headache treated with a PEMF for 15 days after failingacupuncture and medications get effective relief of migraine, tension,and cervical headaches at about 1 month after treatment (Prusinski etal., 1987). They have at least a 50% reduction in frequency or intensityof the headaches and reduction in analgesic drug use. Cluster andposttraumatic headaches do not respond as well.

PEMFs of various kinds, strengths, and frequencies included have beenfound to have good results in a wide array of painful conditions. Thereis little risk when compared to the potential invasiveness of othertherapies and the risk of toxicity, addiction, and complications frommedications. This creates an ideal setup for clinicians to attempt PEMFsbefore other more potentially harmful treatments are attempted,especially for long-term treatment of chronic pain conditions.

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SUMMARY OF THE INVENTION

A system and method is provided for applying a low strength, lowfrequency magnetic field therapy to biological tissues.

A low frequency oscillating current is passed through a coil configuredto induce a magnetic field strength of about 0.01-5 mTesla at a distanceof 1 cm from the coil (or a cover over the coil), at a pulse frequencywithin the range 0.5-1,000 Hz, and more generally 5-1,000 Hz, forexample at 100 Hz. The coil is e.g., 5-200 turns, having a diameter of2-20 mm, of 0.2 mm copper wire, with a hollow core.

With each rising and falling edge of a pulse (e.g., square wave), theinductor coil establishes a magnetic field that oscillates with afrequency spectrum that is dependent on the risetime and falltime of thepulse. A pulse occurs with each transition (edge of the square wave), ofalternating polarity. The circuit acts as a filter, and with a qualityaudio amplifier with sufficient headroom driving the circuit, the pulseswill contain strong frequency components at 10-24 kHz. Thus, the signalemitted from the coil will typically be a low frequency square wavemagnetic field at the pulse edge rate, i.e., double the 0.5-1,000 Hzpulse rate, and a high frequency emission that may be an underdampedoscillation, overdamped oscillation, or critically damped oscillationwithin the decay period that accompanies each edge transition, dependenton the amplifier and circuit components. Due to the power storage in theinductive coil and capacitor during excitation with the square wave, thepeak power of the damped oscillation is not directly related to thepower output capacity of the audio amplifier that drives the circuit,though the average power will generally be so limited.

Typically, the sharper the edge of the pulse, the greater the highfrequency components in the electrical signal. With a quality audioamplifier driven by a digital to analog converter designed for digitalaudio sources, the frequency range may be flat (e.g., <3 dB rolloff)to >20 kHz, with a digital sampling rate of ˜44.1 kHz (or in some cases,196 kHz). However, in such audio circuits, the digital source typicallyexceeds the bandwidth of the analog signal, and the typical audio rangeextends to about 20 kHz, so the amplifier may have a low pass filter(smoothing filter) which reduces “digital noise” above 20 kHz. Thecurrent is preferably controlled by a smartphone or other programmabledevice, and may be provided through an audio jack or other mechanicalelectronics connector. Alternately, a digital interface and/or wirelessinterface may control the current. An app on the smartphone may be usedto control the frequency, amplitude/envelope modulation, waveform,duration, etc. of the oscillation. The coil may be in mineral or plastichousing with a simple filter, and TRRS-type audio jack.

A circuit may be provided which resonates, e.g., at a frequency below100 kHz, and in particular which causes a ringing upon abrupt change ina voltage applied to the circuit. Thus, a pulse train (symmetric orasymmetric) may be received by the device comprising the circuit and thecoil, which is excited by the pulses, and resonates with a decay uponeach transition. Typically, the circuit is passive, but in someembodiments, it contains diodes, transistors, integrated circuits, orthe like. For example, some audio amplifiers may seek to damp theringing within the circuit, and therefore it may be advantageous toinclude active or passive edge sharpening electronics within the device,which can be achieved through use of semiconductors, e.g., a digitalcontrol or analog devices that have nonlinear transfer functions andthose that act as “triggers”.

There is an emerging trend to eliminate an audio amplifier within asmartphone, which is replaced with a wireless interface (e.g.,Bluetooth) or a wired interface. Therefore, while a passive device iscurrently preferred for use with smartphones or other programmabledevices that have their own analog audio interface, the technology mayalso be used with active circuits that internally generate theexcitation for the coil. However, while the device can autonomouslygenerate the pulsed electromagnetic field (PEMF) therapy, it ispreferred that the controlling device be connected to an on-linecommunications network for upload of feedback, user input, and sensordata, and download of therapy plans and excitation parameters.Therefore, one aspect of the technology is to provide a PEMF device thatis part of the “Internet of Things”. However, because of the possibilityof interference between the communications of the device and the therapyto be administered, in a preferred embodiment, communications are notconcurrent with therapy. This, however, may be dependent on a number offactors, and is not a required attribute in all cases.

The smartphone may control the device to apply a therapy according tovarious theories. The device is not limited to any particular set ofexcitation parameters, and indeed a particular advantage is that atherapist can design different regimens using the same system. Likewise,while this is not required, the smartphone provides a convenient meansfor patient feedback, and may thus permit an adaptive therapy. In thecase of acute pain relief, the smartphone may employ a genetic algorithmto explore various treatment parameters, seeking for a particularpatient the optimum, which may vary over time. A remote server mayreceive feedback (which may be anonymized in some cases), allowing thevarious states of the genetic algorithm to be tested over a largepopulation, which can therefore reveal patient subpopulations andgroups, and expand the testing space to a degree larger than possiblewith a single patient.

It is preferred that, if the smartphone is in close proximity to thepatient at the time of therapy, that the therapy be applied with thesmartphone in “airplane mode”, that is, with radio frequencycommunications from the phone deactivated. This will avoid exposing thepatient to potentially harmful high frequency waves during the therapy.Therefore, required remote communications are buffered for transmissionafter the therapy is concluded. Likewise, any required parameterdownloads must be complete prior to initiation of therapy.

The coil is advantageously disposed within a spherical housing, whichmay have a bored cylindrical hole for the coil, and an electricalconnector extending therefrom. Based on current technologies, a 3.5 mmphono jack or TRRS jack is available on many smartphones. However, somedevices do not have this interface available. Therefore, anotheravailable interface may be used, such as a wired digital interface, suchas USB (2, 3, 3.1, etc.), Thunderbolt, etc., and wireless interfaces,such as WiFi, Bluetooth, NFC, Zigbee, Zwave, etc.

The device does not need a smartphone or other standardintelligent/programmable consumer device, and for example, may be drivenby an internal microcontroller, AM or FM radio receiver, analog ordigital circuitry, etc. However, a smartphone is advantageous because itpermits relatively easy programming, and remote communications as may beappropriate. Note that as technologies advance, the form factor andsuite of functionality in a “smartphone” may evolve. Since the PEMFtherapy is not dependent on the phone per se, any device that suitablygenerates excitation for the coil, and accepts and responds to controlparameters for generating the PEMF, may be used. According to presentavailability and ubiquity of smartphones and tablets, e.g., Android,Apple, Windows (e.g., mobile), Linux, Chrome, Blackberry OS, etc., thistype of platform is convenient, capable and preferred.

It is therefore an object to provide a magnetic field therapy device,comprising: a conductive coil fed with a current, to supply a therapy toa tissue, the therapy comprising a magnetic field strength below 50 mT,preferably below 25 mT, more preferably below 10 mT, and most preferablybelow 5 mT, and may have a strength as low as 0.01 mT max. Preferably,the field penetrates into the tissue at least 1 cm.

The coil may be, for example, a single layer of between 5 and 200 turns,e.g., 0.2 mm copper wire, having an external diameter of between about 2mm and 20 mm.

The excitation received by the circuit which excites the coil, may be anoscillating electrical signal having a frequency range from about 5 Hzto about 100 kHz.

The circuit may present an impedance of at least 8 Ohms at 100 Hz to adriver circuit.

The signal which drives the circuit may have a slew rate of ˜10 kHz,e.g., 1 V/100 μS=10⁵ V/sec, and the circuit may have a nominal loadimpedance of 33Ω for signals having that slew rate.

The coil (and optionally circuit) may be contained within a housing,such as a spherical magnetically impermeable material, such as a mineral(natural or synthetic), polymer, or non-magnetic metal. The housing isconfigured to contact the skin, and thus permit a therapy of the tissuesunderneath the skin.

A filter may be provided, optionally within the housing, having at leastone pole within a range of 5 Hz to 50,000 Hz, configured to filter theoscillating electrical signal supplied to the conductive coil. Thefilter may resonate upon transient changes in voltage. The filter mayhave a pole at about 3 kHz.

The conductive coil may have a diameter of about 5-10 or 10-12 mm, andpreferably about 6-8 mm. The conductive coil may have a diameter of lessthan about 15 or 12 mm. The size and shape of the coil are governed bythe laws of physics with respect to the magnetic field shape andstrength. Thus, a deeper field typically requires a larger coil, whichwill require a higher current. If the coil is to be driven from an audioearphone jack amplifier, the maximum power available will be <200 mW,and typically <100 mW, corresponding to 1 V max into >8 Ohms. Forexample, with a 33 Ohm load resistor in the circuit, and a 1 V peakdriven signal, the available average power will be about 30 mW. Thepresented impedance may be at least 30 Ohms.

The oscillating electrical signal may have a frequency range comprising50 Hz. That is, the signal may assume a 50 Hz frequency, or be abroadband signal encompassing 50 Hz.

The cover may have a spherical surface having a diameter of about 15-30mm preferably 20-25 mm, and most preferably 20 mm.

The cover may be formed of a magnetically impermeable mineral, such asquartz.

The input may comprise an analog phono jack, such as a 3.5 mm TRRS phonojack.

The input may also comprise a digital audio connector.

The filter may comprise a circuit board having at least one resistor andat least one capacitor.

The input may comprise a radio frequency receiver, the magnetic fieldtherapy device further comprising a self-contained battery power sourceto power the radio frequency receiver and the conductive coil.

The input may be adapted to receive a signal from a smartphone. Thesmartphone may be configured to generate the oscillating electricalsignal based on a downloadable app which executes under a smartphoneoperating system. The smartphone may be configured to execute thedownloadable app in airplane mode, substantially without emission ofradio frequency signals in excess of 25 MHz.

It is also an object to provide a magnetic field therapy method,comprising: providing a conductive coil, an input configured to receivean oscillating electrical signal and to supply a current to theconductive coil, to thereby generate an oscillating magnetic fieldsurrounding the conductive coil, and a cover, surrounding the conductivecoil and the filter, adapted to contact human or animal skin and passthe oscillating magnetic field substantially without distortion orattenuation; generating the oscillating electrical signal in a firststate with a smartphone under control of a smartphone app; and emittingthe generated oscillating magnetic field surrounding the conductive coilinto the human or animal skin adjacent to the cover, at a magnetic fieldstrength of at least 0.01 mTesla at a distance of 1 cm from the cover.The method may further comprise receiving a user input to thesmartphone; and generating the oscillating electrical signal in a secondstate with the smartphone under control of the smartphone app, thesecond state comprising a different distribution of frequencies of theoscillating electrical signal than the first state.

Under excitation by the oscillating electrical signal at a voltage of 1V peak-to-peak, a magnetic field of between 0.01 mTesla and 5 mTesla maybe obtained within a human or animal tissue under the human or animalskin contacting a surface of the cover at a depth of 1 cm from thesurface of the cover, aligned with an axis of the conductive coil.

An electrical filter may be provided within the cover. The electricalfilter may comprise a circuit board having at least one resistor and atleast one capacitor. The filter may have a pole at about 3 kHz.

The conductive coil may have an inner diameter of about 8 mm. Thepresented impedance at the input may be at least 30 Ohms, e.g., having a33Ω resistor in series with the coil. This value is dependent on typicalsmartphone audio amplifier designs, and a 33Ω load impedance at 10 kHzis typically acceptable for such amplifiers in common devices. Ofcourse, with a particular device, the value of the load impedance (andthus the amount of power that is available for the PEMF) can vary.

The oscillating electrical signal may have a frequency range comprising50 Hz.

The cover may comprise a spherical section having a diameter of about 2cm. The cover may be formed of a magnetically impermeable mineral.

The method may further comprise generating, on a display of thesmartphone, an indication of at least a direction in which the covershould be moved over the human or animal skin.

The magnetic field excited for a 100 Hz oscillating electrical signal ata voltage of 1 V peak-to-peak may be at least 0.05 mTesla at a depth of1 cm in the human or animal tissue beneath the human or animal skincontacting the surface of the cover.

The input may comprise an analog phono jack or a digital audioconnector.

The input may comprise a radio receiver, and the magnetic field therapydevice may further comprise a self-contained battery power source topower the radio receiver and the current to the conductive coil.

The smartphone may execute the downloadable app in airplane mode,substantially without emission of radio frequency signals in excess of25 MHz.

The oscillating electrical signal may be a square wave signal.

The circuit within the device may, for example, have a non-lineartransfer function semiconductor device which conducts or triggers in avoltage dependent manner, and therefore generates high frequency signalcomponents from a signal transition. For example, a diode “turns on” at0.3-0.6 V in forward conduction (depending on junction composition). Apair of back-to-back diodes thus would be operative for “edgesharpening” for both rising and falling pulses. Similarly, a bipolartransistor/JFET/FET circuit may provide greater control over theconduction threshold and frequency characteristics. Other types ofsemiconductor devices may also be used in a passive circuit.

The circuit may also contain an active semiconductor device. Forexample, the power in the audio signal may be harvested with a rectifiercircuit (preferably germanium or Schottky diodes or FETs, due to the lowoperating voltages) and stored on a capacitor, which is then used to runthe active circuit. A voltage multiplier or step-up circuit may beemployed as appropriate. A separate power source may also be provided,independent of the audio signal.

Note that the pulse signal is typically a square wave, but in practice,this need not have a symmetric duty cycle. Preferably, the spacingbetween upswing and downswing of the pulses is greater than the settlingtime of the coil and capacitor circuit, though in some cases, it may beshorter, allowing a relatively continuous excitation of the magneticfield therapy. All characteristics of the excitation signal may becontrolled within the digital parameters of the control circuit and theanalog characteristics of the amplifier and other circuit components,under control of the software in the smartphone or other control device.

It is also an object to provide a method of treating a human or animal,comprising: providing a smartphone having a magnetically actuatedacoustic speaker; placing the speaker proximate to skin; generating anacoustic emission from the acoustic speaker and an accompanying magneticemission, within a frequency range of 10 Hz-1000 Hz, controlled with adownloadable application for the smartphone; receiving user feedbackinto the smartphone downloadable application representing a subjectivetherapeutic effect; and modifying the acoustic emission based on thefeedback.

It is a further object to provide a method of treating a human oranimal, comprising: providing a smartphone having an electromagneticvibration motor; placing the electromagnetic vibration motor proximateto skin; generating a vibration from the electromagnetic vibration motorand an accompanying magnetic emission, controlled with a downloadableapplication for the smartphone; receiving user feedback into thesmartphone downloadable application representing a subjectivetherapeutic effect; and modifying the vibration based on the feedback.

It is another object to provide a pulsed electromagnetic field therapydevice, comprising: an interface configured to receive an oscillatingelectrical signal from a programmable device; a coiled conductor, havingat least 5 turns, and an inner diameter of between about 4-15 mm; amagnetically impermeable cover, having an outer surface configured forcontact with human or animal skin; and a circuit within the magneticallyimpermeable cover, configured to excite the coiled conductor with acurrent corresponding to the oscillating electrical signal, to generatea magnetic field of between about 10 μTesla and 5 mTesla at a distanceof 1 cm from the cover at a position axially aligned with the coiledconductor.

The interface may comprise an analog audio interface, presenting animpedance of between about 8-100 Ohms. The coiled conductor may comprisecopper wire. The circuit may comprise a resistor and a capacitor.

The magnetically permeable cover may comprise a natural or syntheticmineral.

The pulsed electromagnetic field therapy device may further comprise alight emitting diode configured to illuminate in an emission patterncorresponding to an amplitude of the oscillating electric signal.

The interface may comprise a Bluetooth, WiFi, Zigbee, Zwave, or NearField Communication protocol receiver.

The interface may comprise a 3.5 mm headphone jack analog audiointerface, presenting an impedance of between about 8-100 Ohms.

The interface may comprise a microphone.

The circuit may comprise a capacitor in series with the coiledconductor.

It is another object to provide a pulsed electromagnetic field therapymethod, comprising: receiving a pulse train from a programmable device,having a pulse frequency of between 5-1,000 Hz; passing a currentcorresponding to the pulse train through a coiled conductor having aninner diameter of between about 4-15 mm, within a cover configured tocontact an exposed surface of a subject; emitting a pulseelectromagnetic field from the coiled conductor corresponding to thecurrent, having a maximum field strength of between about 10 μTesla and5 mTesla at a distance of 1 cm from the cover at a position axiallyaligned with the coil coiled conductor, to thereby apply a pulsedelectromagnetic field therapy to the subject.

The programmable device may comprise a mobile telecommunication devicehaving an application program downloaded through a telecommunicationport, the application program controlling an audio interface of themobile telecommunication device to generate the pulse train, andcontrolling a user interface of the mobile telecommunication device toreceive user input to at least initiate generation of the pulse train.

The method may further comprise receiving feedback from the subjectrelating to an effect of the pulsed electromagnetic field therapy.

The method may further comprise communicating a signal corresponding tothe feedback from the mobile telecommunication device to a remote serverthrough a communication network.

The method may further comprise receiving from the remote server a setof parameters for controlling generation of the pulse train. The set ofparameters may comprise a pulse train frequency, and a pulse trainduration.

The electromagnetic field therapy may comprise a resonant discharge ofstored energy from the coiled conductor.

The passing a current corresponding to the pulse train through a coiledconductor may comprise passing the current through a capacitor and thecoiled conductor.

The cover may have a spherical surface. The spherical surface may have adiameter of between 15 and 25 mm, e.g., about 20 mm.

The power for emission of the pulsed electromagnetic field therapy maybe derived from the received pulse train or from a self-contained powersource distinct from the pulse train.

The method may further comprise producing an optical signal when thepulsed electromagnetic therapy is in progress. The power for generatingthe optical signal may be derived from the received pulse train or aself-contained power source distinct from the pulse train. The pulsetrain may be received wirelessly. The pulse train may be receivedthrough a Bluetooth, WiFi, or NFC receiver, or an analog headphone jack,presenting a load of at least 30 Ohms, for example. The pulse train mayalso be received as an acoustic communication through a microphone.

The programmable device may generate an analog output having a pluralityof different programmable sampling rates, further comprising selecting asampling rate to alter the pulsed electromagnetic field therapy. Theplurality of different programmable sampling rates comprise 44.1 kHz, 48kHz, and 96 kHz. The pulse train may be a square wave pulse train. Thepulse train may have a symmetric or asymmetric duty cycle.

It is a further object to provide a pulsed electromagnetic field therapymethod, comprising: receiving a pulse signal from a programmable device,having a pulse repetition rate of between 5-1,000 pulses per second;passing a current corresponding to the pulse train through a coiledconductor having an inner diameter of between about 4-15 mm, within acover configured to contact an exposed surface of a subject, the currenthaving an asymmetric rise and fall; and emitting a pulse electromagneticfield from the coiled conductor corresponding to the current, having amaximum field strength of between about 10 μTesla and 5 mTesla at adistance of 1 cm from the cover at a position axially aligned with thecoil coiled conductor, to thereby apply a pulsed electromagnetic fieldtherapy to the subject.

It is another object to provide a magnetic field therapy device,comprising: a conductive coil having a diameter of between about 8 mmand 15 mm and having between 5-1000 turns; an analog input configured toreceive an electrical signal from an analog audio interface device, ahigh pass filter; and a non-magnetic cover, surrounding the conductivecoil and the filter, adapted separate the conductive coil from contactwith an adjacent human or animal tissue substantially without disruptinga magnetic field emitted from the conductive coil, wherein underexcitation by the electrical signal comprising square wave pulses at afrequency of 100 Hz and a voltage of 1 V peak-to-peak, a magnetic fieldof between 0.01 mTesla and 5 mTesla maximum is obtained at a distance of1 cm from the cover.

The filter may comprise a resistor having a resistance of between about10 Ohms and 100 Ohms, and a ceramic capacitor having a capacitance ofabout 1-50 μFarads, and the coiled conductor has between 5 and 200turns.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic of an electrical circuit according to thepresent invention.

FIG. 2 shows a physical arrangement of a preferred embodiment of theinvention.

FIG. 3 shows an assembled view of a preferred embodiment of theinvention with a spherical case.

FIG. 4 shows an example of the device, plugged into a headphone jack ofa smartphone, being used to apply a therapy to an upper arm region.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the technology provides a small device thatcan be plugged into a standard headphone jack socket on any smartphone(Android or iPhone) and used with a downloaded software app.

A jackplug holder may also be provided so the device can be worn as anecklace when not in use. A keyring embodiment may also be provided.

The schematic is simple, consisting of 4 components, as shown in FIG. 1: A 16 turn (single layer) coil, 7.8-8 mm diameter, 0.2 mm enameledcopper wire, on a P14 hollow core former (Farnell, 235-5082), in serieswith a 33 Ohm 0.1 W resistor in parallel with a 10 μF, >10 V ceramiccapacitor (e.g., 1210 case, Farnell 249-7164). The resistor andcapacitor are mounted to a 8-10 mm PCB (e.g., 0.6 mm FRP) soldered tothe jackplug sleeve solder tag. The end of the coil and the resistor andcapacitor are mounted on, and connected to, the tip and ring 2 contactsof a 3.5 mm TRRS headphone jack. The coil is inserted into a 20 mm glassor mineral ball, such as a quartz sphere with a bored 8-10 mm dimeter,15-18 mm deep cylindrical, glued or epoxied to the end of the TSSR jack(Lumberg 1532 02 Phone Audio Connector, Plug, 3.5 mm, 4 Contacts, CableMount, Plastic Body, Nickel Plated Contacts, Farnell 2101773). Thearrangement is shown in FIG. 2 .

The resistor and capacitor can be housed inside the bobbin to reducetotal length of device.

The excitation through the headphone jack may be e.g., a 100 Hz squarewave.

According to one theory, all frequencies used can be considered asmusical tone frequencies when the all tones are tuned to the keynote453.3 Hz—which is an important proton resonance. When more than onefrequency is concurrently used, a musical chord may be generated. It isnoted that it is unlikely that tissues respond to musical theory.However, the PEMF can excite afferent nerves and be communicated to thebrain, which can then respond centrally or through efferent pathways.

The frequencies may have a symphonic quality, and as such need not besimple square waves, and rather may be arbitrary waveforms withdynamically changing frequencies.

The fundamental frequencies, in fact, may extend to 10 kHz, and perhapsbeyond.

FIG. 3 shows an assembled view of a preferred embodiment of theinvention with a spherical case natural semi-transparent mineral case,showing the coil wound around a bobbin centrally located within thesphere, and a TRRS phono jack extending axially from the sphere. Amineral sphere (e.g., amethyst) was been found to be ergonomically andaesthetically acceptable, with respect to mass, thermal capacity(relevant to skin contact), magnetic characteristics, etc.

The device may be conveniently provided with a necklace-holder, whichhas a dummy TRRS socket to retain the device when not in use. Thenecklace provides a convenient way to carry and transport the device. Acorresponding holder may be formed as a keyring, or the like.

FIG. 4 shows an example of the device, in use, plugged in to theheadphone jack of a typical cellphone. The cellphone may be operated in“airplane mode”, and the app may enforce this as a restriction of use,in order to avoid potential interference between radio frequencyemissions from the radio(s) within the phone and the PEMF. An exceptionmay be the use of Bluetooth to communicate the signal to the device,though it is preferred to have no RF emissions from the phone duringPEMF therapy. Because the PEMF is preferably generated based a squarewave (a digital type signal), it may be possible to program a digitalinterface (e.g., USB) to generate the excitation signal for the device,rather than the audio output of the cellphone.

a downloadable smartphone app according to the present technology may beprovided, having various interface screens. In the first screen, asplash screen may be provided. Typically, during PEMF therapy, it isdesired to provide a relaxing environment, and the screens should bedesigned with muted colors, and avoidance of distractions. In the secondscreen, a set of different programs may be provided, which generatedifferent output excitation signal patterns, such as “pain relief”,“muscle tension”, and “relaxation”. The interface may also provide auser history option and a setup option. The “pain relief” screen isexemplary, and may include relevant user-identification information(name, birthdate, gender), body location to be treated, an intensitycontrol slider, a PEMF therapy duration input, and a “start” screenbutton. This screen input may be used to represent a pre-treatment(subjective) evaluation of the patient condition.

During therapy, soothing patterns which optionally correspond to thetreatment protocol may be shown on the screen, and may be animatedaccordingly.

A personalized user screen may show a summary of a treatment session,and provide a control button to stop the therapy. The app may also sensewhen the device is removed from the headphone jack, and preferablyimmediately cease generation of the excitation signal to avoid drivingthe internal phone speaker with the square wave pulses. The screen mayprovide an input for the patient to provide a post-treatment(subjective) evaluation, which can be used to track the therapy.

The app can also receive input from the user, post treatment, to providesubjective response factors. In some cases, objective data may beavailable. For example, where a vascular response to the therapy occurs,skin color, temperature, edema measurements, etc., may be acquiredeither automatically or manually, and input into the system. Theseinputs, either on an individual basis or on a population basis, may beused to tailor the therapy for the individual, for example by changingpulse frequency and/or duty cycle, pulse amplitude, therapy duration, orvarious patterns of excitation pulses. In some cases, the therapy may beresponsive to the environment, for example, ambient temperature orillumination, and the smartphone can detect these parameters.

It is believed that various forms of musical phrasing, in particularstyles of classical music, are particularly appropriate for PEMF.Therefore, the excitation parameters may model classic works, such aspatterns and amplitudes of excitation pulses, combinations of excitationparameters (similar to musical chords), etc. As discussed above, it isunclear that the peripheral tissues are capable of particularlyresponding to these signals, but rather that communications from theperiphery to the central nervous system are involved.

What is claimed is:
 1. A magnetic therapy device, comprising: aninterface configured to receive an audio spectrum electrical signalcomprising energy at a frequency of 1,000 Hz, from an audio signal port;a coil having an internal diameter of between 4 mm and 15 mm and havingat least 5 turns, configured to emit a magnetic field in response to theaudio spectrum electrical signal; an impedance load device having atleast one pole within a range of 5 Hz to 50,000 Hz configured to presenta predetermined minimum impedance of at least 8Ω at 100 Hz to the audiosignal port; and a shell, surrounding the coil, configured to permit themagnetic field to pass therethrough undistorted.
 2. The magnetic therapydevice according to claim 1, wherein the magnetic field has a fieldstrength of between 0.01 mTesla and 5 mTesla at a distance of 1 cm fromthe shell in response to an oscillating electrical signal at a voltageof 1 V peak-to-peak at 100 Hz.
 3. The magnetic therapy device accordingto claim 1, wherein the impedance load device presents an impedance ofat least 33 Ohms in response to an audio spectrum electrical signalhaving a slew rate of 10⁵ V/sec, to the audio signal port.
 4. Themagnetic therapy device according to claim 1, wherein the impedance loaddevice presents an impedance of between 8 and 100 Ohms to the audiosignal port and the coil has a maximum field strength between 0.1 and 15mT at a distance of 1 cm from the shell in response to the audiospectrum electrical signal.
 5. The magnetic therapy device according toclaim 1, wherein the shell comprises a spherical surface having adiameter of at least 2 cm.
 6. The magnetic therapy device according toclaim 1, wherein the impedance load device comprises a circuit boardhaving at least one resistor and at least one capacitor.
 7. The magnetictherapy device according to claim 1, wherein the impedance load devicehas a transfer function having a pole at about 3 kHz.
 8. The magnetictherapy device according to claim 1, wherein the interface comprises aphono jack.
 9. The magnetic therapy device according to claim 1, whereinthe interface comprises a Bluetooth receiver.
 10. The magnetic therapydevice according to claim 1, in combination with a smartphone undercontrol of a smartphone app, wherein the audio spectrum electricalsignal is received from the smartphone.
 11. The magnetic therapy deviceaccording to claim 10, wherein the smartphone app is configured toreceive a user input to the smartphone, to produce oscillating magneticfields corresponding to the audio spectrum electrical signal having atleast two different states, under control of the smartphone app,comprising a first state with a different distribution of frequenciesthan a second state.
 12. A magnetic therapy method, comprising:receiving an audio spectrum electrical signal comprising energy at afrequency of 1,000 Hz from an audio signal port, into an impedance loaddevice having at least one pole within a range of 5 Hz to 50,000 Hzwhich presents a predetermined minimum impedance of at least 8Ω at 100Hz to the audio signal port; emitting a magnetic field in response tothe audio spectrum electrical signal from a coil having an internaldiameter of between 4 mm and 15 mm and having at least 5 turnssurrounded with a shell, configured to permit the magnetic field to passtherethrough undistorted, having a maximum field strength between 0.1and 15 mT at a distance of 1 cm from the shell in response to the audiospectrum electrical signal; and defining the audio spectrum electricalsignal with a smartphone app on a smartphone.
 13. The magnetic therapymethod according to claim 12, wherein the smartphone app receives a userinput to the smartphone, and the coil produces oscillating magneticfields corresponding to the audio spectrum electrical signal having atleast two different states, under control of the smartphone app,comprising a first state with a different distribution of frequenciesthan a second state.
 14. The magnetic therapy method according to claim12, wherein the magnetic field is emitted with a maximum field strengthof between 0.01 mTesla and 5 mTesla at a distance of 1 cm from the shellin response to an oscillating electrical signal at a voltage of 1 Vpeak-to-peak at 100 Hz.
 15. The magnetic therapy method according toclaim 12, wherein the impedance load device presents an impedance ofbetween 8 and 100 Ohms to the audio signal port.
 16. The magnetictherapy method according to claim 12, wherein the shell comprises aspherical surface having a diameter of at least 2 cm.
 17. The magnetictherapy method according to claim 12, wherein the audio signal portcomprises a Bluetooth receiver.
 18. The magnetic therapy methodaccording to claim 12, further comprising: receiving a user input to thesmartphone to control the smartphone app; generating the audio spectrummagnetic field based on an audio output of the smartphone comprising afirst distribution of frequencies; and generating the audio spectrummagnetic field based on an audio output of the smartphone comprising asecond distribution of frequencies different from the first distributionof frequencies.
 19. The magnetic therapy method according to claim 12,further moving the shell with respect to skin during emission of theaudio spectrum magnetic field.
 20. A electromagnetic field therapydevice, comprising: a coil having an internal diameter of between 4 mmand 15 mm and having at least 5 turns, configured to emit an oscillatingmagnetic field corresponding to an audio spectrum signal comprisingenergy at a frequency of 1,000 Hz from a smartphone, under control of asmartphone app; a shell, having an outer surface configured for contactwith human or animal skin, which does not perturb the oscillatingmagnetic field; and a circuit having at least one pole within a range of5 Hz to 50,000 Hz within the cover, configured to electrically filterthe audio spectrum signal and present an impedance to a signal source ofat least 8 Ohms at 100 Hz, the electromagnetic field therapy devicebeing configured to generate the oscillating magnetic field having amagnetic field strength between about 10 μTesla and 5 mTesla at adistance of 1 cm from the shell.